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1
Baskin, Jerry M., Juan J. Lu, Carol C. Baskin, and Dun Y. Tan. "The necessity for testing germination of fresh seeds in studies on diaspore heteromorphism as a life-history strategy." Seed Science Research 23, no. 2 (May 10, 2013): 83–88. http://dx.doi.org/10.1017/s096025851300010x.
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AbstractMany studies have compared diaspore dispersal ability and degree of dormancy in the two diaspores of dimorphic plant species. A primary goal of these studies was to determine if germination and dispersal characteristics of the two morphs fit within a high risk–low risk (bet-hedging) life-history strategy, i.e. high dispersal/low dormancy in one morph versus low dispersal/high dormancy in the other one. In a survey of 26 papers on 28 diaspore dimorphic species, we found that in 12 of the studies, which were published between 1978 and 2008, seeds were stored, and thus possibly afterripened, before they were tested for germination. The 14 papers that tested fresh seeds were published between 1963 and 2010. Failure to test fresh seeds likely resulted in misinterpretation of the diaspore dispersal/dormancy strategy in some of the species investigated. We conclude that it is imperative that fresh seeds be tested for germination in order to be certain that the correct relationship between dispersal and dormancy is elucidated, and thus that the correct interpretation is made concerning life-history strategy and bet-hedging, in dimorphic species.
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Wichmann, Matthias C., Matt J. Alexander, Merel B. Soons, Stephen Galsworthy, Laura Dunne, Robert Gould, Christina Fairfax, Marc Niggemann, Rosie S. Hails, and James M. Bullock. "Human-mediated dispersal of seeds over long distances." Proceedings of the Royal Society B: Biological Sciences 276, no. 1656 (September 30, 2008): 523–32. http://dx.doi.org/10.1098/rspb.2008.1131.
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Human activities have fundamental impacts on the distribution of species through altered land use, but also directly by dispersal of propagules. Rare long-distance dispersal events have a disproportionate importance for the spread of species including invasions. While it is widely accepted that humans may act as vectors of long-distance dispersal, there are few studies that quantify this process. We studied in detail a mechanism of human-mediated dispersal (HMD). For two plant species we measured, over a wide range of distances, how many seeds are carried by humans on shoes. While over half of the seeds fell off within 5 m, seeds were regularly still attached to shoes after 5 km. Semi-mechanistic models were fitted, and these suggested that long-distance dispersal on shoes is facilitated by decreasing seed detachment probability with distance. Mechanistic modelling showed that the primary vector, wind, was less important as an agent of long-distance dispersal, dispersing seeds less than 250 m. Full dispersal kernels were derived by combining the models for primary dispersal by wind and secondary dispersal by humans. These suggest that walking humans can disperse seeds to very long distances, up to at least 10 km, and provide some of the first quantified dispersal kernels for HMD.
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Tsuji, Yamato, Kumugo Yangozene, and Tetsuya Sakamaki. "Estimation of seed dispersal distance by the bonobo, Pan paniscus, in a tropical forest in Democratic Republic of Congo." Journal of Tropical Ecology 26, no. 1 (December 8, 2009): 115–18. http://dx.doi.org/10.1017/s0266467409990290.
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Great apes are considered to be important seed dispersers in palaeotropical habitats due to their large body size (this would be reflected in the amount of foods consumed) and large home ranges (Poulsen et al. 2001, Wrangham et al. 1994). Furthermore, the great apes might process seeds in a way that maintains their viability (Lambert 1999). Previous studies of seed dispersal by great apes have generally taken the form of lists of seeds found in their faeces (Voysey et al. 1999a, Wrangham et al. 1994), effects of passage through their guts on seed germination (Idani 1986, Wrangham et al. 1994), and effects of dispersal location on germination/seedling survival (Gross-Camp & Kaplin 2005, Rogers et al. 1998, Voysey et al. 1999b). In contrast with the richness of reports about aspects of seeds after their dispersal, few studies have investigated the dispersal pattern of seeds. In this study, we report on the estimated distances of seed dispersal by the wild bonobo (Pan paniscus Schwartz), a species of great ape.
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Liu, Xiaoguang, Yuhong Zeng, Gabriel Katul, Wenxin Huai, and Yu Bai. "Longitudinal dispersal properties of floating seeds within open-channel flows covered by emergent vegetation." Advances in Water Resources 144 (October 2020): 103705. http://dx.doi.org/10.1016/j.advwatres.2020.103705.
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Loebach, Christopher A., and Roger C. Anderson. "Measuring short distance dispersal of Alliaria petiolata and determining potential long distance dispersal mechanisms." PeerJ 6 (March 15, 2018): e4477. http://dx.doi.org/10.7717/peerj.4477.
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Introduction Alliaria petiolata, an herbaceous plant, has invaded woodlands in North America. Its ecology has been thoroughly studied, but an overlooked aspect of its biology is seed dispersal distances and mechanisms. We measured seed dispersal distances in the field and tested if epizoochory is a potential mechanism for long-distance seed dispersal. Methods Dispersal distances were measured by placing seed traps in a sector design around three seed point sources, which consisted of 15 second-year plants transplanted within a 0.25 m radius circle. Traps were placed at intervals ranging from 0.25–3.25 m from the point source. Traps remained in the field until a majority of seeds were dispersed. Eight probability density functions were fitted to seed trap counts via maximum likelihood. Epizoochory was tested as a potential seed dispersal mechanism for A. petiolata through a combination of field and laboratory experiments. To test if small mammals transport A. petiolata seeds in their fur, experimental blocks were placed around dense A. petiolata patches. Each block contained a mammal inclusion treatment (MIT) and control. The MIT consisted of a wood-frame (31 × 61× 31 cm) covered in wire mesh, except for the two 31 × 31 cm ends, placed over a germination tray filled with potting soil. A pan filled with bait was placed in the center of the tray. The control frame (11 × 31 × 61 cm) was placed over a germination tray and completely covered in wire mesh to exclude animal activity. Treatments were in the field for peak seed dispersal. In March, trays were moved to a greenhouse and A. petiolata seedlings were counted and then compared between treatments. To determine if A. petiolata seeds attach to raccoon (Procyon lotor) and white-tailed deer (Odocoileus virginianus) fur, wet and dry seeds were dropped onto wet and dry fur. Furs were rotated 180 degrees and the seeds that remained attached were counted. To measure seed retention, seeds were dropped on furs and rotated as before, then the furs were agitated for one hour. The seeds retained in the fur were counted. Results For the seed dispersal experiment, the 2Dt function provided the best fit and was the most biologically meaningful. It predicted that seed density rapidly declined with distance from the point source. Mean dispersal distance was 0.52 m and 95% of seeds dispersed within 1.14 m. The epizoochory field experiment showed increased mammal activity and A. petiolata seedlings in germination trays of the MIT compared to control. Laboratory studies showed 3–26% of seeds were attached and retained by raccoon and deer fur. Retention significantly increased if either seed or fur were wet (57–98%). Discussion Without animal seed vectors, most seeds fall within a short distance of the seed source; however, long distance dispersal may be accomplished by epizoochory. Our data are consistent with A. petiolata’s widespread distribution and development of dense clusters of the species in invaded areas.
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Hanson, Thor, Steven Brunsfeld, Bryan Finegan, and Lisette Waits. "Conventional and genetic measures of seed dispersal for Dipteryx panamensis (Fabaceae) in continuous and fragmented Costa Rican rain forest." Journal of Tropical Ecology 23, no. 6 (October 29, 2007): 635–42. http://dx.doi.org/10.1017/s0266467407004488.
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The effects of habitat fragmentation on seed dispersal can strongly influence the evolutionary potential of tropical forest plant communities. Few studies have combined traditional methods and molecular tools for the analysis of dispersal in fragmented landscapes. Here seed dispersal distances were documented for the tree Dipteryx panamensis in continuous forest and two forest fragments in Costa Rica, Central America. Distance matrices were calculated between adult trees (n = 283) and the locations of seeds (n = 3016) encountered along 100 × 4-m transects (n = 77). There was no significant difference in the density of seeds dispersed > 25 m from the nearest adult (n = 253) among sites. There was a strong correlation between the locations of dispersed seeds and the locations of overstorey palms favoured as bat feeding roosts in continuous forest and both fragments. Exact dispersal distances were determined for a subset of seeds (n = 14) from which maternal endocarp DNA could be extracted and matched to maternal trees using microsatellite analysis. Dispersal within fragments and from pasture trees into adjacent fragments was documented, at a maximum distance of 853 m. Results show no evidence of a fragmentation effect on D. panamensis seed dispersal in this landscape and strongly suggest bat-mediated dispersal at all sites.
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O'Connor, Julie M., David M. Burrows, Benjamin L. Allen, and Scott E. Burnett. "Is the European red fox a vector of the invasive basket asparagus (Asparagus aethiopicus) in eastern Australia?" Australian Mammalogy 42, no. 2 (2020): 204. http://dx.doi.org/10.1071/am19001.
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Basket asparagus (Asparagus aethiopicus) has become a naturalised invasive plant in some coastal areas of Australia since its introduction in the late 19th century. Its spread through garden waste dumping and avian seed dispersal has been well documented and both are considered to be the primary means of dispersal. While a small number of avian vectors have been identified, no Australian studies have investigated the potential of mammals to disperse basket asparagus seeds. We collected basket asparagus seeds from fox (Vulpes vulpes) scats collected in the field, confirmed the viability of these seeds in germination trials, and further documented the germination of basket asparagus seeds from an undisturbed fox scat in situ. These results demonstrate that foxes consume and disperse basket asparagus seeds, and that these seeds are viable and germinate under field conditions. Foxes not only use basket asparagus stands as harbour, but can also facilitate the plant’s dispersal in coastal ecosystems.
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Vanderhoff, Elizabeth Natasha, and Brian Grafton. "Behavior of tamarins, tanagers and manakins foraging in a strangler fig (Ficus sp.) in Suriname, South America: implications for seed dispersal." Biota Neotropica 9, no. 3 (September 2009): 419–23. http://dx.doi.org/10.1590/s1676-06032009000300039.
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The behavior of foragers can directly affect the dispersal of seeds. Strangler figs are keystone resources throughout the tropics and are important resources for both primates and birds. We examined the foraging behavior of golden-handed tamarins and four bird species in a strangler fig to see how these behaviors might affect the dispersal of fig seeds. Tamarins removed fruit at a faster rate than did any of the bird species examined. Additionally, tamarins tended to swallow figs whole whereas birds tended to drop figs once they were processed. Tamarins visiting fig trees ingest large quantities of fig seeds that may be deposited throughout the forest. Birds on the other hand tended to slowly process fruits near the fig tree and drop processed fruit containing large quantities of seeds. Future studies need to be conducted to ascertain differences in post dispersal seed fate.
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Black, Michael. "Darwin and seeds." Seed Science Research 19, no. 4 (December 2009): 193–99. http://dx.doi.org/10.1017/s0960258509990171.
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AbstractIn 2009, the bicentenary of Charles Darwin's birth on 12 February 1809 is being celebrated. For seed scientists, celebrations of the contributions of the great biologist should also mark his involvement with seeds. Darwin was interested in seeds, particularly in their role in dispersal and distribution of plant species over long distances. His studies of seeds, laid down in several books and articles, contributed to the development of his ideas on evolution and the distribution of living organisms on the planet. In this review, the place of seeds in Darwin's work is surveyed and it is shown how he referred to them to support and illustrate some of his most important ideas.
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Reiserer, Randall S., Gordon W. Schuett, and Harry W. Greene. "Seed ingestion and germination in rattlesnakes: overlooked agents of rescue and secondary dispersal." Proceedings of the Royal Society B: Biological Sciences 285, no. 1872 (February 7, 2018): 20172755. http://dx.doi.org/10.1098/rspb.2017.2755.
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Seed dispersal is a key evolutionary process and a central theme in the population ecology of terrestrial plants. The primary producers of most land-based ecosystems are propagated by and maintained through various mechanisms of seed dispersal that involve both abiotic and biotic modes of transportation. By far the most common biotic seed transport mechanism is zoochory, whereby seeds, or fruits containing them, are dispersed through the activities of animals. Rodents are one group of mammals that commonly prey on seeds (granivores) and play a critical, often destructive, role in primary dispersal and the dynamics of plant communities. In North America, geomyid, heteromyid and some sciurid rodents have specialized cheek pouches for transporting seeds from plant source to larder, where they are often eliminated from the pool of plant propagules by consumption. These seed-laden rodents are commonly consumed by snakes as they forage, but unlike raptors, coyotes, bobcats, and other endothermic predators which eat rodents and are known or implicated to be secondary seed dispersers, the role of snakes in seed dispersal remains unexplored. Here, using museum-preserved specimens, we show that in nature three desert-dwelling rattlesnake species consumed heteromyids with seeds in their cheek pouches. By examining the entire gut we discovered, furthermore, that secondarily ingested seeds can germinate in rattlesnake colons. In terms of secondary dispersal, rattlesnakes are best described as diplochorous. Because seed rescue and secondary dispersal in snakes has yet to be investigated, and because numerous other snake species consume granivorous and frugivorous birds and mammals, our observations offer direction for further empirical studies of this unusual but potentially important channel for seed dispersal.
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Westelaken, Irene L., and M. A. Maun. "Spatial pattern and seed dispersal of Lithospermum caroliniense on Lake Huron sand dunes." Canadian Journal of Botany 63, no. 1 (January 1, 1985): 125–32. http://dx.doi.org/10.1139/b85-015.
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Studies on spatial pattern and seed dispersal of Lithospermum caroliniense (Walt.) MacMill. on Lake Huron sand dunes revealed that the ratio of pin to thrum plants was approximately 1: 1 on the south slope of the first dune ridge and slack. However, thrum plants had a higher proportion than pin plants on the crest of the dune ridge. The density of plants was highest on the south slope as compared with the other topographical zones. The spatial pattern of plants was nonrandom and plants were clustered in each of the three topographical zones. Most dispersed seeds of L. caroliniense remained within 1 m of the parent plant. The seed dispersal was not radially symmetrical around the parent plant. The steepness of the dune slope affected the dispersal distance of some propagules. Some seeds were retained on the parent, but few of these seeds were normal. About 40 to 64% of the recovered seeds contained holes in the seed coat. Eight months after marking, about one-third of the original marked seeds were still intact.
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Czarnecka, Joanna, Grzegorz Orłowski, and Jerzy Karg. "Endozoochorous dispersal of alien and native plants by two palearctic avian frugivores with special emphasis on invasive giant goldenrod Solidago gigantea." Open Life Sciences 7, no. 5 (October 1, 2012): 895–901. http://dx.doi.org/10.2478/s11535-012-0081-9.
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AbstractThe role of frugivorous birds in dispersal of the seeds of fleshy-fruited plants is well understood, but other groups of birds like granivores and omnivores can also act as vectors, especially in the process of non-standard dispersal. In this study we examined the role of two widely distributed birds (the Eurasian Blackbird, Turdus merula, and the Black Redstart, Phoenicurus ochruros) in seed dispersal. We analyzed the content of 279 droppings of the Black Redstart collected between July and October and 85 droppings of the Eurasian Blackbird collected during January. In total we found 366 seeds, representing 11 plant taxa, in the faecal samples; 93% of the seeds belonged to fleshy-fruited species. The most numerous were two native taxa, Sambucus racemosa/nigra, in summer and autumn, Crataegus monogyna in winter, and one alien species Morus alba, which is dispersed in summer. We also found seeds of four dry-fruited species; the most interesting of which was the presence of anemochorous seeds of Solidago gigantea (a highly invasive alien species). The seeds were found only in droppings of the Eurasian Blackbird. Considering the obtained results the need for further studies on bird-plant interactions should be a priority.
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Wehner, Katja, Lea Schäfer, Nico Blüthgen, and Karsten Mody. "Seed type, habitat and time of day influence post-dispersal seed removal in temperate ecosystems." PeerJ 8 (March 13, 2020): e8769. http://dx.doi.org/10.7717/peerj.8769.
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Seed survival is of great importance for the performance of plant species and it is strongly affected by post-dispersal seed removal by either different animals such as granivorous species and secondary dispersers or abiotic conditions such as wind or water. The success of post-dispersal seed removal depends on seed specific traits including seed size, the presence of coats or elaiosomes, the mode of seed dispersion, and on the habitat in which seeds happen to arrive. In the present study we asked how seed traits (dehulled vs. intact; size; dispersal mode), habitat (forest vs. grassland), and time of day (night vs. day) influence post-dispersal seed removal of the four plant species Chelidonium majus, Lotus corniculatus, Tragopogon pratensis and Helianthus annuus. Seed removal experiments were performed in three regions in Hesse, Germany. The results showed different, inconsistent influences of time of day, depending on habitat and region, but consistent variation across seed types. C. majus and dehulled H. annuus seeds had the fastest removal rates. The impact of the habitat on post-dispersal seed removal was very low, only intact H. annuus seeds were removed at significantly higher rates in grasslands than in forests. Our study demonstrates consistent differences across seed types across different habitats and time: smaller seeds and those dispersed by animals had a faster removal rate. It further highlights that experimental studies need to consider seeds in their natural form to be most realistic.
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Galindo-González, Jorge, Guillermo Vázquez-Domínguez, Romeo A. Saldaña-Vázquez, and Jesús R. Hernández-Montero. "A more efficient technique to collect seeds dispersed by bats." Journal of Tropical Ecology 25, no. 2 (March 2009): 205–9. http://dx.doi.org/10.1017/s0266467409005859.
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Seeds dispersed and deposited by wind, animals and other dispersal agents are a fundamental component of natural forest succession, plant regeneration and population maintenance, aside from increasing a population's genetic pool in tropical ecosystems (Henry & Jouard 2007, Muscarella & Fleming 2007, Wilson & Traveset 2000). Frugivorous bats and birds are ideal vectors for long-distance seed dispersal; therefore, studies of the food habits of frugivores and the specific identities of the dispersers are essential for understanding ecological patterns and processes in tropical environments. Studies related to succession processes, the frequency, number and composition of seeds dispersed by animals are essential in order to generate new data and hypotheses, consequently the method and quality of obtaining data are important.
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Souza, Juliane M., and Roberto Iannuzzi. "Dispersal Syndromes of fossil Seeds from the Lower Permian of Paraná Basin, Rio Grande do Sul, Brazil." Anais da Academia Brasileira de Ciências 84, no. 1 (March 2012): 43–68. http://dx.doi.org/10.1590/s0001-37652012000100006.
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The morphological analysis of seeds has been an important subject in modern ecological studies, once it provides evidence about the biology and adaptations of the parent plant. However, this kind of study has been restricted to the ecology of modern plants and is rarely used in interpretations of Paleozoic data. From the understanding of dispersal syndromes analysis as an important tool to paleoecological reconstruction, this study provides a first approach using this tool with seeds from the Lower Permian strata of southern Paraná Basin in Rio Grande do Sul. Based on previously classified seeds and using their biological and taphonomic data, the syndrome of dispersal was interpreted, and their placement in successional groups (pioneer, early-successional and later-successional) was suggested. Seven morphospecies were analyzed: Samaropsis gigas, representing a later-successional species living in water bodies with hydrochory as its dispersal syndrome; Samaropsis kurtzii, typical of early-successional species showing anemochory as its dispersal syndrome and living in distal areas in relation to water bodies; Samaropsis aff. S. millaniana, Cordaicarpus aff. C. brasilianus, Cordaicarpus cerronegrensis and Cordaicarpus truncata have typical characteristics of pioneer plants, exhibiting barochory as their primary dispersal syndrome with other syndromes associated.
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Donohue, Kathleen. "Seeds and seasons: interpreting germination timing in the field." Seed Science Research 15, no. 3 (September 2005): 175–87. http://dx.doi.org/10.1079/ssr2005208.
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This paper discusses how field and laboratory experiments, using a variety of genetic material, can be combined to investigate the genetic basis of germination under realistic ecological conditions, and it reviews some of our recent work on germination phenology ofArabidopsis thalianain the field. Our results indicate that the genetic basis of germination depends on the environment. In particular, the conditions during seed maturation interact with post-dispersal environmental factors to determine germination phenology, and these interactions have a genetic basis. Therefore genetic studies of germination need to consider carefully the environment – both during seed maturation and after dispersal – in which the experiments are conducted in order to characterize genetic pathways involved with germination in the field. Laboratory studies that explicitly manipulate ecologically relevant environmental factors can be combined with manipulative field studies. These studies can identify the particular environmental cues to which seeds respond in the field and characterize the genetic basis of germination responses to those cues. In addition, a variety of genetic material – including mutant and transgenic lines, intact natural genotypes, recombinant genotypes, and near isogenic lines – can be used in field studies as tools to characterize genetic pathways involved in germination schedules under natural ecological conditions.
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Lovas-Kiss, Ádám, Judit Sonkoly, Orsolya Vincze, Andy J. Green, Attila Takács, and Attila Molnár V. "Strong potential for endozoochory by waterfowl in a rare, ephemeral wetland plant species, Astragalus contortuplicatus (Fabaceae)." Acta Societatis Botanicorum Poloniae 84, no. 3 (2015): 321–26. http://dx.doi.org/10.5586/asbp.2015.030.
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It was proposed previously that passive dispersal by migratory aquatic birds explain the widespread distribution of many wetland organisms. Several experimental studies have shown that many widespread wetland plant species can be readily dispersed within the guts of Anatidae. However, it is unclear whether plants with a more restricted distribution are able to disperse via waterbirds. This paper addresses the dispersal ability and germination ecology of the little-known Hungarian milkvetch <em>Astragalus contortuplicatus</em>, which occurs on banks of continental rivers and has a limited and unpredictable distribution. To test whether limited capacity for endozoochory by waterfowl could explain the sporadic appearance of this species, we force-fed ten captive mallards (<em>Anas platyrhynchos</em>) with 100 milkvetch seeds each. Droppings were collected for up to 45 h after feeding. Intact and viable seeds were found in the droppings of each mallard, and altogether 24.7% of seeds fed were recovered intact. The proportion of retrieved seeds that germinated (27.0%) was significantly higher than that of untreated control seeds (0.5%), but significantly lower than that of mechanically scarified seeds (96.0%). Retrieved seeds that germinated developed into healthy mature plants. Given the average flight velocity of mallards, seeds of <em>A. contortuplicatus</em> may travel up to 1600 km inside the digestive tract of migrating individuals. Our results suggest that avian vectors may be more important for the dispersal of rare higher plants (especially those with a hard seed-coat) than hitherto considered. Moreover, they suggest that rarity does not necessarily indicate limited dispersal ability, and may instead be explained by specific habitat requirements.
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Taghizadeh, M. S., M. E. Nicolas, and R. D. Cousens. "Effects of relative emergence time and water deficit on the timing of fruit dispersal in Raphanus raphanistrum L." Crop and Pasture Science 63, no. 10 (2012): 1018. http://dx.doi.org/10.1071/cp12246.
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Seed dispersal is both a spatial and a temporal phenomenon, although most studies focus on spatial aspects. Seed initiation on the maternal plant may occur over a considerable period, especially in indeterminately flowering species, and thus seeds may be exposed to a wide range of environmental conditions during their development. The result is variation in the timing of seed development, the anatomy of structures related to the dispersal process, and the behaviour and fate of seeds post-dispersal. A key resource during the growth and development of summer-maturing species in most areas, and one that is thus likely to modify these processes, is water. Two experiments were therefore undertaken to describe (i) the development of Raphanus raphanistrum fruits and the timing of fruit dispersal, and (ii) the effects of water availability on the timing of fruit dispersal. Fewer seeds were produced and subsequently dispersed by later emerging plants. The duration of fruit dispersal became shorter when the plants emerged progressively later than the crop, and the time of maximum dispersal was later. For cohorts of fruits initiated at the same time, those that developed under mild and severe water deficit reached their final length sooner, and were dispersed sooner, than those receiving a plentiful supply of water. Thus, the phenology of the maternal plant and the nature of its environment can modify the timing of propagule maturity and consequently dispersal. Such information may provide an opportunity for managers to reduce weed seed return to their field or, conversely, to regulate the amount of contaminated grain or reduce dispersal to other locations.
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Barnett, Adrian A., Sarah A. Boyle, Liliam P. Pinto, Waldete C. Lourenço, Thais Almeida, Welma Sousa Silva, Beatriz Ronchi-Teles, et al. "Primary seed dispersal by three Neotropical seed-predating primates (Cacajao melanocephalus ouakary, Chiropotes chiropotes and Chiropotes albinasus)." Journal of Tropical Ecology 28, no. 6 (November 2012): 543–55. http://dx.doi.org/10.1017/s0266467412000600.
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Abstract:The Neotropics house two guilds of large arboreal vertebrate seed predators: parrots and the pitheciin primates. Both have diets dominated by immature fruits. The possibility of members of the Pitheciinae (genera Cacajao, Chiropotes and Pithecia) acting as occasional seed dispersers has been mooted, but not experimentally shown. We combined primate behavioural data and seed germination data from three separate field studies in the Brazilian states of Amazonas and Pará to analyse patterns of post-consumption seed survivorship for seeds discarded by three pitheciin species (Cacajao melanocephalus ouakary, Chiropotes chiropotes and Chiropotes albinasus). We then calculated the frequency of dispersal events for four species eaten by C. m. ouakary. All three primate species dropped intact seeds while feeding, and 30.7% of 674 dropped seeds germinated ex situ. Undamaged seeds from unripe and ripe samples germinated (29.3% and 42.7%, respectively), and all three primate species carried some fruits up to 20 m from the parent tree before consuming them. Potential seed-dispersal events varied from 1 (Macrolobium acaciifolium) per fruiting cycle to more than 6500 (Duroia velutina), suggesting that there are differences in dispersal potential. In summary, although they are highly specialized seed predators, these primates may also act as important dispersers for some plant species, and effective dispersal is not restricted to ripe fruits, as immature fruits removed from a tree may continue to mature and the seeds later germinate, a much-neglected aspect of dispersal ecology. The possibility that similar events occur in parrots should be experimentally investigated.
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Moses, Kara L., and Stuart Semple. "Primary seed dispersal by the black-and-white ruffed lemur (Varecia variegata) in the Manombo forest, south-east Madagascar." Journal of Tropical Ecology 27, no. 5 (August 2, 2011): 529–38. http://dx.doi.org/10.1017/s0266467411000198.
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Abstract:Seed dispersal is a pivotal ecological process but remains poorly understood on Madagascar, where lemurs are key dispersers. The black-and-white ruffed lemur (Varecia variegata) possesses many behavioural and ecological attributes potentially conducive to effective seed dispersal, but no studies have investigated dispersal patterns in this species. This 3-mo study quantified aspects of the primary seed dispersal patterns generated by two Varecia variegata groups (7 individuals). Feeding and ranging behaviour was quantified using behavioural observation (345.6 h), dispersal quantity and seed identity was determined by faecal analysis, and 10-wk germination trials tested effects of gut passage on germination of four species. Individual lemurs dispersed an estimated 104 seeds d−1, of 40 species. Most seeds were large (>10 mm); the largest was 42 mm long. Gut passage was rapid (mean 4.4 h) and generally increased germination speed and success. Mean and maximum inferred dispersal distances were 180 and 506 m respectively; low compared with many anthropoids, but possibly typical of lemurs. Though limited by a short study period, results suggest that the ruffed lemur is an effective disperser of seeds and possibly a critical disperser of large-seeded species which other frugivores cannot swallow. Loss of large-bodied seed dispersers such as Varecia variegata may have far-reaching ecological consequences including impacts on forest structure and dynamics.
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Skarpaas, Olav, Richard Auhl, and Katriona Shea. "Environmental variability and the initiation of dispersal: turbulence strongly increases seed release." Proceedings of the Royal Society B: Biological Sciences 273, no. 1587 (December 6, 2005): 751–56. http://dx.doi.org/10.1098/rspb.2005.3366.
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Dispersal is a critical process in ecology. It is an important biological driver of, for example, invasions, metapopulation dynamics, spatial pattern formation and pathogen movement. Much is known about the effect of environmental variability, including turbulence, on dispersal of diaspores. Here, we document experimentally the strong but under-explored influence of turbulence on the initiation of dispersal. Flower heads of two thistle species ( Carduus nutans and Carduus acanthoides ) with ripe seeds were exposed to series of laminar and turbulent air flows of increasing velocity in a wind tunnel. Seed release increased with wind speeds for both laminar and turbulent flows for both species. However, far more seeds were released, at significantly lower wind speeds, during turbulent flows. These results strongly suggest a need for more quantitative studies of abscission in the field, as well as dispersal models that incorporate variability in the diaspore release phase.
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POULSEN, JOHN R., CONNIE J. CLARK, and THOMAS B. SMITH. "Seed dispersal by a diurnal primate community in the Dja Reserve, Cameroon." Journal of Tropical Ecology 17, no. 6 (November 2001): 787–808. http://dx.doi.org/10.1017/s0266467401001602.
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Multiple species of primate disperse seeds and differentially contribute to the seed rain in tropical forests. The goal of this study was to examine seed dispersal by a primate community of five monkey and two ape species in the Dja Reserve, Cameroon. The density of primates in the reserve was calculated to be 77 individuals km-2. Analysis of 5789 faecal clumps demonstrated that 40% of monkey and 74% of ape faecal clumps possessed whole seeds. Six of the seven focal species acted as seed dispersers; faecal clumps passed by the black-and-white colobus (Colobus guereza) did not contain any whole seeds during the study. Seed passage trials on four captive monkey species showed monkeys to have an average seed passage time of 22 hours and defecation rate of five times per day. From the above results, the primate community was estimated to defecate 1129 seeds km-2 d-1. Seeds passed by the primate community came from 125 species of trees, lianas and shrubs, equivalent to at least 34% of the known tree flora. Rarefaction curves indicated that additional collection effort would identify more seed species passed by primates. Germination studies demonstrated that primate-passed seeds are viable. The number of seeds and plant species dispersed suggests that the primate community plays an important role in the maintenance of forest structure.
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Greene, D. F., and E. A. Johnson. "Fruit abscission in Acer saccharinum with reference to seed dispersal." Canadian Journal of Botany 70, no. 11 (November 1, 1992): 2277–83. http://dx.doi.org/10.1139/b92-283.
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Winged fruits and seeds travel approximately twice as far as predicted by micrometeorological models of seed dispersal by the wind. We hypothesize that seeds preferentially abscise at higher velocities because the motive force for abscission is drag (proportional to the square of the wind velocity). A 3-year study of fruit abscission in Acer saccharinum L., supplemented by experimental studies, demonstrates that for this species (i) separation layers develop rapidly when relative humidity is low (the early afternoon in a typical diurnal relative humidity cycle), and (ii) the exponents in power law equations relating abscission rate to wind speed are somewhat higher than the expected value of 2.0. Consequently, micrometeorological models of dispersal must be modified to account for the nonrandom nature of abscission. Key words: seed dispersal, abscission, Acer saccharinum.
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Camacho, Carlos, Marc-Olivier Beausoleil, Julio Rabadán-González, and Roxanne Richard. "Nest building by Darwin’s finches as an overlooked seed dispersal mechanism." Journal of Tropical Ecology 35, no. 1 (December 11, 2018): 43–45. http://dx.doi.org/10.1017/s0266467418000378.
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AbstractCaliochory, or seed dispersal by birds as nest material, has been reported for several species, but its effectiveness remains unclear in most cases. Darwin’s finches are traditionally regarded as seed predators, but the observation of two nests challenges this assumption by demonstrating that they can act as seed dispersers via caliochory. Darwin’s finches incorporate cotton-like materials into their nests, including seeds of Darwin’s cotton (Gossypium darwinii), a shrub endemic to the Galápagos (Ecuador). Bird nests typically break down after intense rainfall, so the seeds incorporated into nests might benefit from suitable conditions for germination. By simulating the germination conditions experienced over a 72-h period by cotton seeds in a naturally fallen nest, this study qualitatively confirms the long-term viability of at least a small fraction of the seeds at the surface of the nest. Darwin’s finches might therefore provide seed-dispersal services to Darwin’s cotton and possibly, other native and exotic plants of the Galápagos commonly incorporated into nests. However, larger confirmatory studies are needed.
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O'Farrill, Georgina, Sophie Calmé, Raja Sengupta, and Andrew Gonzalez. "Effective dispersal of large seeds by Baird's tapir: a large-scale field experiment." Journal of Tropical Ecology 28, no. 1 (December 8, 2011): 119–22. http://dx.doi.org/10.1017/s0266467411000599.
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Even though the full process of seed dispersal is the combination of movement mode and distance, deposition, successful germination and survival (Nathan 2006, Westcott et al. 2005), relatively few studies have documented the role of mammals as facilitators of germination and survival (Paine & Harms 2009). In particular, the effectiveness of large terrestrial mammals (>50 kg) as effective dispersers of large seeds is poorly known, but has been linked to the treatment of the seeds in their digestive system, the deposition of viable seeds in nutrient-rich environments (faeces) and favourable sites. Other aspects related to long-distance movements, defecation patterns and home-range size are frequently cited as factors that favour the deposition of seeds far from parent trees, which is expected to reduce predation and intraspecific competition, and enhance fitness (Schupp et al. 2002). We addressed these issues through a large-scale field experiment.
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Gagic-Serdar, Renata, Z. Poduska, I. Djordjevic, G. Cesljar, Svetlana Bilibajkic, Lj Rakonjac, and R. Nevenic. "Suppression of indigo bush with pod pests." Archives of Biological Sciences 65, no. 2 (2013): 801–6. http://dx.doi.org/10.2298/abs1302801g.
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The recorded seed predators of Amorpha fruticosa L., indigo bush weevils and pteromalid wasps, were the subject of laboratory and field research studies in the period from 2006 to 2011. Sample analyses were carried out on more than 30 localities in Serbia with the aim of measuring the summarized pre-dispersal and post dispersal predation preferences. The percentages of the total pre-dispersal (max?33%) and post-dispersal re-infested material (over 95%), make these insects serious candidates for host-plant suppression. Their bionomics were monitored through continuous collection, dessection and observation of infested seeds, in correlation with environmental parameters, especially water-level fluctuations in endangered forests.
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Gomes, VGN, ZGM Quirino, and HFP Araujo. "Frugivory and seed dispersal by birds in Cereus jamacaru DC. ssp. jamacaru (Cactaceae) in the Caatinga of Northeastern Brazil." Brazilian Journal of Biology 74, no. 1 (February 2014): 32–40. http://dx.doi.org/10.1590/1519-6984.15312.
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Studies of the dispersal modes of plants aid our understanding of the dynamics of resource and its availability for dispersal agents. The present work sought to characterize the fruiting patterns of the native Caatinga (dryland) cactus Cereus jamacaru, identify its principal dispersers, and evaluate the effects of seed passage through digestive tract of dispersers on its germination. Cereus jamacaru present an annual fruiting pattern and fruiting peaks occurred during June/2009 and February/2010. A total of 135 visits by nine species of resident Caatinga bird species were recorded. The most frequent visiting bird species were Paroaria dominicana and Euphonia chlorotica. Length of bird visits varied from 15 seconds to 4 minutes and seeds removed by birds travelled 10.6 ± 11.2 m until dispersers make the first landing perch, in some cases more than 40 meters away. Germination tests show birds had a high quantity of viable seeds of C. jamacaru in its feces. Seeds that passed through the digestive tract of birds showed a similar germinability of the seeds of the control group. However, the seeds dispersed by birds showed lowest mean germination time related to the control group seeds. This study highlights the potential role of birds as seed dispersers of C. jamacaru, swallowing the whole seeds and defecating intact seeds, accelerating the germination process and transporting seeds away from the mother plant.
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Razafindratsima, Onja H. "Post-dispersal seed removal by rodents in Ranomafana rain forest, Madagascar." Journal of Tropical Ecology 33, no. 3 (April 24, 2017): 232–36. http://dx.doi.org/10.1017/s0266467417000104.
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Abstract:Seed-consuming rodents are increasingly recognized for their roles in the maintenance of tree species diversity, by acting on crucial post seed-dispersal processes. Yet, studies examining the extent to which rodents may act as secondary seed dispersers and/or predators in Madagascar's forests are limited. Thread-marking seed experiments were run to address this, using the seeds of two native large-seeded, frugivore-dispersed tree species (Abrahamia thouvenotii and Cryptocarya crassifolia), in disturbed and less-disturbed habitats in the rain forests of Ranomafana National Park, during the dry season. Data show that post-dispersal handling of seeds by rodents (predation and removal) was significantly lower in disturbed than in less-disturbed habitats (1.31–3.78 times lower; n = 2200). Also, seeds were more likely to be predated or left on the forest ground after removal than being larder- or scatter-hoarded: 27–78% of the removed seeds were found on the ground, <12% found in burrows and there was no evidence of scatter-hoarding (n = 132). Based on pictures from camera traps, the native rodent species, Nesomys rufus, was potentially responsible for seed predation and/or removal in the less-disturbed habitat; but no indication of the rodent species active in the disturbed habitat was obtained. The lack of scatter-hoarding suggests a limited role of rodents in secondary seed dispersal in this system. These findings form a preliminary account of the potential roles of rodents in post seed-dispersal processes in Madagascar's forests, but this warrants further study.
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Liu, Huiliang, Daoyuan Zhang, Xuejun Yang, Zhenying Huang, Shimin Duan, and Xiyong Wang. "Seed Dispersal and Germination Traits of 70 Plant Species Inhabiting the Gurbantunggut Desert in Northwest China." Scientific World Journal 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/346405.
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Seed dispersal and germination were examined for 70 species from the cold Gurbantunggut Desert in northwest China. Mean and range (3 orders of magnitude) of seed mass were smaller and narrower than those in other floras (5–8 orders of magnitude), which implies that selection favors relatively smaller seeds in this desert. We identified five dispersal syndromes (anemochory, zoochory, autochory, barochory, and ombrohydrochory), and anemochorous species were most abundant. Seed mass (F=3.50,P=0.01), seed size (F=8.31,P<0.01), and seed shape (F=2.62,P=0.04) differed significantly among the five dispersal syndromes and barochorous species were significantly smaller and rounder than the others. There were no significant correlations between seed mass (seed weight) (P=0.15), seed size (P=0.38), or seed shape (variance) (P=0.95) and germination percentage. However, germination percentages differed significantly among the dispersal syndromes (F=3.64,P=0.01) and seeds of ombrohydrochorous species had higher germination percentages than those of the other species. In the Gurbantunggut Desert, the percentage of species with seed dormancy was about 80%. In general, our studies suggest that adaptive strategies in seed dispersal and germination of plants in this area are closely related to the environment in which they live and that they are influenced by natural selection forces.
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Couvreur, Martine, Martine Couvreur, Bart Vandenberghe, Kris Verheyen, and Martin Hermy. "An experimental assessment of seed adhesivity on animal furs." Seed Science Research 14, no. 2 (May 2004): 147–59. http://dx.doi.org/10.1079/ssr2004164.
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Epizoochory is widely recognized as an effective long-distance seed dispersal mechanism. Nevertheless, few studies have focused on the investigation of its influencing factors. One of the key aspects of epizoochory is the adhesive interaction between seeds and furs. We describe a new method to quantify experimentally and standardize the adhesivity of seeds to animal fur, as a measure of epizoochorous dispersal potential. The method excludes the impact of animal behaviour and environmental factors, and allows the ranking of species according to their adhesivity score. We measured adhesivity scores for 66 species on the furs of seven mammals. Deep furs with long, rough, undulated hairs implanted at a large angle were most suited for seed adhesion, while seeds adhered less well to shallow furs with short, smooth, straight hairs implanted at small angles. Seeds with specialized adhesive appendages had higher adhesivity scores than seeds with unspecialized appendages and seeds without appendages. However, an interaction effect between certain seed and fur types exists. Although seed morphology is a good predictor for seed adhesivity on fur, less well-adhering seed types often still have relatively high adhesivity scores. Therefore, it is likely that nearly all species are, to some extent, able to disperse epizoochorously.
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Sahley, Catherine Teresa, Klauss Cervantes, Edith Salas, Diego Paredes, Victor Pacheco, and Alfonso Alonso. "Primary seed dispersal by a sigmodontine rodent assemblage in a Peruvian montane forest." Journal of Tropical Ecology 32, no. 2 (March 2016): 125–34. http://dx.doi.org/10.1017/s0266467416000043.
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Abstract:We examined quantity and quality components of primary seed dispersal for an assemblage of sigmodontine rodents in a high-elevation montane tropical forest in Peru. We collected faecal samples from 134 individuals belonging to seven rodent species from the subfamily Sigmodontinae (Cricetidae) over a 2-y period. We conducted seed viability tests for seeds found in faecal samples. We identified seeds from eight plant families (Bromeliaceae, Annonaceae, Brassicaceae, Ericaceae, Melastomatacae, Myrtaceae, Rosaceae, Solanaceae), nine genera and 13 morphospecies. The most abundant seeds belonged toGaultheriasp. 1 (46% of total) andMiconiasp. 1 (31% of total), while the most viable seeds belonged toGreigiasp. (84% viability) andGuatteriasp. (80% viability). We utilized relative rodent abundance, seed species diversity, seed abundance and seed viability per rodent species to calculate an index of rodent disperser effectiveness, and found thatThomasomys kalinowskiiwas the most effective disperser, followed byAkodon torques,Calomys sorellus,Thomasomys oreas,Oligoryzomys andinusandMicroryzomys minutus. Plant genera dispersed by sigmodontine rodents overlapped more with bird- and terrestrial-mammal-dispersed plants than with bat-dispersed plants. Future neotropical seed dispersal studies should consider small rodents as potential seed-dispersers, especially in tropical habitats where small-seeded, berry-forming shrubs and trees are present.
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González-Varo, Juan P., Juan M. Arroyo, and Pedro Jordano. "Who dispersed the seeds? The use of DNA barcoding in frugivory and seed dispersal studies." Methods in Ecology and Evolution 5, no. 8 (June 30, 2014): 806–14. http://dx.doi.org/10.1111/2041-210x.12212.
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Yadok, Biplang G., Pierre-Michel Forget, Daniel Gerhard, Babale Aliyu, and Hazel Chapman. "Seed nutrient content rather than size influences seed dispersal by scatterhoarding rodents in a West African montane forest." Journal of Tropical Ecology 36, no. 4 (July 2020): 174–81. http://dx.doi.org/10.1017/s0266467420000127.
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AbstractRodents can be important in seed dispersal through their scatterhoarding behaviour, yet, the seed traits that are most influential in seed removal by Afrotropical scatterhoarding rodents remains unclear. Here, we investigated the effect of seed size and nutrient content of four seed species on the scatterhoarding behaviour of rodents in an Afromontane forest, Ngel Nyaki forest, Nigeria. To do this we marked with thread-tags the seeds of Santiria trimera, Beilschmedia mannii, Carapa oreophila and Anthonotha noldeae and observed their fate. We predicted that (1) caching frequency would be higher for larger than smaller seed species; (2) caching frequency would be higher for nutrient-rich than nutrient-poor seeds; (3) larger seeds would be taken across farther distances; and (4) survival of cached seeds would be higher for nutrient-rich seeds. In contrast to studies elsewhere we found no difference in caching probabilities based on seed size, although nutrient-rich (high fat content) seeds had a higher probability of being predated than seeds with lower fat content. Larger and smaller seeds were dispersed over the same distances and nutrient-poor (high fibre content) seeds survived longer in seed caches. Overall, our findings suggest that large, nutrient-rich seed species are less likely to be dispersed by rodents.
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Lu, Juan J., Yuan M. Zhou, Dun Y. Tan, Carol C. Baskin, and Jerry M. Baskin. "Seed dormancy in six cold desert Brassicaceae species with indehiscent fruits." Seed Science Research 25, no. 3 (July 6, 2015): 276–85. http://dx.doi.org/10.1017/s0960258515000215.
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AbstractThe dispersal unit of many species of Brassicaceae is an indehiscent fruit, but relatively few studies have tested the effect of the pericarp on seed germination in this family. Our aim was to determine the effect of the pericarp on seed dormancy in six species of Brassicaceae native to the cold desert of north-west China. Intact dispersal units and isolated seeds of Chorispora sibirica, Euclidium syriacum, Goldbachia laevigata, Spirorrhynchus sabulosus, Sterigmostemum fuhaiense and Tauscheria lasiocarpa were stored dry at ambient laboratory conditions for 0–12 months and tested for germination in light and in dark at 5/2, 15/2 and 30/15°C. The amount of water absorbed by fruits and by seeds within the fruits was determined. For four species, intact fruits, isolated seeds and isolated seeds plus the removed pericarps were used to test for the mechanical versus possible chemical role of the pericarp in seed dormancy. Fresh isolated seeds, which have a fully developed embryo, germinated to lower percentages and rates than afterripened seeds. Thus, seeds have non-deep physiological dormancy. The pericarp significantly reduced germination, but inhibition was not due to lack of water uptake by seeds or to chemical inhibitors. Afterripened seeds of the six species germinated to 0–50% inside the fruits. We conclude that the pericarp plays a dominant role in seed dormancy of the six study species, and it does so by mechanically restricting embryo growth. Thus, the pericarp has the potential to spread germination over an extended period of time.
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Grimm, Christoph. "Seed predators and the fruiting phenology of Pithecellobium pallens (Leguminosae) in thornscrub, north-eastern Mexico." Journal of Tropical Ecology 11, no. 3 (August 1995): 321–32. http://dx.doi.org/10.1017/s0266467400008804.
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ABSTRACTLife table studies were conducted on the flowers, pods and seeds of the tree Pithecellobium pallens to assess the extent of damage by the seed predators Stator limbatus and Merobruchus insolitus (Coleoptera: Bruchidae). Brachyacma palpigera (Lepidoptera: Gelechiidae) was also found to feed on the seeds of this tree. Seed predation and herbivore damage destroyed 41% of the seeds. Pods were taken to the laboratory and seed predators within were reared and identified. B. palpigera and M. insolitus were major causes of mortality, whereas damage by S. limbatus was slight. The growth ratio of pods to seeds did not indicate a rapid development of seeds as an evasive strategy against bruchid attack. Experiments showed no successful attack by bruchids on seeds exposed on the ground after dispersal from the tree.
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Cascante-Marín, Alfredo, Noemi von Meijenfeldt, Hanneke M. H. de Leeuw, Jan H. D. Wolf, J. Gerard B. Oostermeijer, and Joannes C. M. den Nijs. "Dispersal limitation in epiphytic bromeliad communities in a Costa Rican fragmented montane landscape." Journal of Tropical Ecology 25, no. 1 (January 2009): 63–73. http://dx.doi.org/10.1017/s0266467408005622.
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Abstract:Transformation of tropical forests is likely to affect seed-dispersal patterns and influence the composition of epiphytic plant communities in human-altered habitats. We tested this hypothesis by carrying out a comparative study of seed influx, survival and growth of transplanted seedlings of epiphytic bromeliads among isolated trees in six pasture areas, six forest edges and six forest sites in a montane area in Costa Rica. In total, 72 traps trapped 1285 seeds over a 2-mo period in the dry season of 2003. For all four investigated bromeliad genera, Catopsis, Guzmania, Tillandsia and Werauhia, the number of trapped seeds in each habitat followed a pattern similar to the number of fruiting individuals in the vicinity of the traps. Traps in forest edges (30) were 1.9 times more likely to collect seeds than traps at forest interiors (30) and pasture trees (12), the latter showing similar probabilities of catching seeds. After 1 y, survival and growth of 3660 transplanted seedlings from three bromeliad species was significantly higher in forest interiors, providing no explanation for the lower abundance of fruiting adults in that habitat. These results suggest that the successful establishment of epiphytic bromeliads in forest interiors is mainly dispersal-limited. If corroborated, differences in abundance among species at each habitat are likely related to differences in growth rates and reproductive success. Further studies on the growth and mortality of seedlings up to the flowering stage, however, are needed.
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McConkey, Kim R. "Influence of faeces on seed removal from gibbon droppings in a dipterocarp forest in Central Borneo." Journal of Tropical Ecology 21, no. 1 (January 2005): 117–20. http://dx.doi.org/10.1017/s0266467404001968.
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Many frugivorous animals disperse seeds in their faeces (Corlett 1998, van der Pijl 1982), which may enhance the ability of secondary seed dispersers and post-dispersal seed predators to locate seeds (Andresen 2001, Chapman 1989, Feer 1999, Janzen 1982). By destroying and moving seeds these animals can radically alter the primary seed shadows generated by frugivorous animals and, consequently, have the potential to influence plant recruitment (Alcántara et al. 2000, Crawley 1992). Nevertheless, the influence of faeces on seed removal in South-East Asian forests has not previously been investigated and our knowledge currently comes from studies in Neotropical forests (Andresen 2001, Chapman 1989, Feer 1999, Janzen 1982).
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Manalil, Sudheesh, Ahmadreza Mobli, and Bhagirath Singh Chauhan. "Competitiveness of windmill grass (Chloris truncata) and feathertop Rhodes grass (Chloris virgata) in mungbean (Vigna radiata)." Crop and Pasture Science 71, no. 10 (2020): 916. http://dx.doi.org/10.1071/cp20092.
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Windmill grass (Chloris truncata R.Br.) and feathertop Rhodes grass (Chloris virgata Sw.) are two weeds of the northern region of Australia that are rapidly expanding in range, being favoured by conservation agricultural systems and prevailing weed management using a narrow pool of herbicides. Information on competitiveness and seed-production dynamics of these weeds is lacking for mungbean (Vigna radiata (L.) Wilczek), a major summer crop in the region. Field studies were conducted to evaluate the effect of different densities of these weed species on crop yield of mungbean in the 2016–17 (2016) and 2017–18 (2017) seasons. Windmill grass reduced mungbean yields by 56% with 39 weed plants m–2 in 2016 and 55% with 47 weed plants m–2 in 2017. Windmill grass produced a maximum of 98708 seeds m–2 in 2016 and 118613 seeds m–2 in 2017, and there was 15–21% seed dispersal at crop harvest. Competition from feathertop Rhodes grass resulted in yield losses of 73% with 49 weed plants m–2 and 65% with 45 weed plants m–2. Feathertop Rhodes grass produced a maximum of 229514 seeds m–2 in 2016 and 367190 seeds m–2 in 2017, and seed dispersal at crop harvest was only 3–7%. Competition from both weed species resulted in a significant reduction in number of pods per m2, grains per pod and 1000-grain weight of mungbean. These results show that windmill grass and feathertop Rhodes are highly competitive against mungbean, and their timely management is crucial for minimising yield loss. Although both weeds produced a substantial number of seeds, seed dispersal at crop harvest was low, especially for feathertop Rhodes grass. The high weed-seed retention relative to maturity of mungbean may help in managing these problematic weeds through various means including weed-seed capturing and destruction
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Kottler, Emily J., and Keryn Gedan. "Seeds of change: characterizing the soil seed bank of a migrating salt marsh." Annals of Botany 125, no. 2 (August 13, 2019): 335–44. http://dx.doi.org/10.1093/aob/mcz133.
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Abstract Background and Aims The capacity for dispersal to promote or hinder species’ responses to global change remains a major question in ecology. One ecosystem experiencing rapid change is the tidal marsh, which is migrating inland in response to accelerated sea level rise. Few studies to date have investigated the ecological dynamics that impact this large-scale migration. Seed dispersal and persistence in the soil seed bank is a component that can be strongly indicative of community trajectories. With this in mind, the aim of our study was to characterize the germinable seed bank across a marsh–forest ecotone in the Chesapeake Bay. Methods Soil samples were collected across transects that ran from the high marsh to the coastal loblolly pine forest in a brackish marsh in Blackwater National Wildlife Refuge, MD, USA. Samples were grown in a greenhouse and watered with either freshwater or 3 ppt seawater solution. We compared community composition across transects and between salinity treatments. Additionally, we compared the seed bank with standing vegetation and used seed trait data from the TRY Database to investigate changes in functional traits along this ecotone. Key Results We found halophytic species dispersing up to 15 m into the forest and a general lack of obligate upland species, including near absence of Pinus taeda, the dominant species in the forest canopy. A majority of species detected in the seed bank were wetland species of various types, with species with wide salinity tolerance arising most frequently. Salinity addition had a significant negative influence on seed bank diversity. Conclusion Overall, our seed bank results suggest that dispersal and germination under the conditions of saltwater intrusion will limit forest regeneration and favour marsh plant dispersal. This indicates that the ecological processes that determine the soil seed bank community will support continued migration of marsh species into uplands.
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Ooi, Mark K. J. "Seed bank dynamics and climate change in semi-arid ecosystems: a focus on physically dormant species." Revista Brasileira de Geografia Física 8 (December 15, 2015): 651. http://dx.doi.org/10.26848/rbgf.v8.0.p651-659.
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The dynamics surrounding seeds are arguably the most important drivers of population persistence in semi-arid ecosystems. To fully understand plant population persistence and, in particular, to predict the impacts of changing climatic conditions, we need to develop a clearer picture of the ecological consequences of variation in seed dormancy and germination. In this review, I focus on seeds with physical dormancy in semi-arid regions, looking at the mechanistic effects of climate on seed bank dynamics. Both pre-dispersal and post-dispersal environment effects are considered. Knowledge is lacking in the understanding of the effects of changing climate on seed production, dormancy-breaking temperature thresholds, seed longevity and seed vigour. While lessons can be learnt from the broader range of studies conducted in the agricultural sector, there is a limit as to how the results from such studies can be applied to wild species in natural ecosystems. A concerted effort to increase the amount of ecological research in native environments is needed to gain a better understanding of the effects of climate change on biodiversity.
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Salazar, Ana, Joyce Maschinski, Jennifer Possley, and Katherine Heineman. "Seed germination of 53 species from the globally critically imperiled pine rockland ecosystem of South Florida, USA: effects of storage, phylogeny and life-history traits." Seed Science Research 28, no. 1 (January 11, 2018): 82–92. http://dx.doi.org/10.1017/s0960258517000332.
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AbstractGermination studies at the community level are crucial for understanding and predicting changes in species distribution patterns, particularly in endangered plant communities. We investigated the effects of dry (11–25% relative humidity) and freezing (–18°C) storage conditions, phylogeny and plant life-history traits (life-form, life-span, microhabitat and seed dispersal mode) on seed germination percentage (GP) and time to reach 50% germination (T50) of 53 species native to pine rocklands in South Florida, USA, a globally critically imperiled ecosystem. Most species we studied (68%) withstood dry and freezing storage conditions and thus ex situ seed banking can assist their long-term conservation. Bayesian mixed effect models revealed that there was a significant phylogenetic signal in GP and T50 across species. Life-history covariates did not explain significant additional variation in GP in models controlling for the phylogenetic relationships among species. T50 differed among species with contrasting dispersal modes, with animal-dispersed seeds exhibiting more delayed germination than wind-dispersed or unassisted seeds. Differential germination responses across species with different seed dispersal modes have implications for potential shifts in species composition under disturbance and climate change. Thus, knowledge of species-relatedness and some life-history traits such as seed dispersal mode can significantly assist management decisions regarding seed storage and conservation of subtropical endangered plants.
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MARTINS, Karina, Raifanny da Silva Oliveira dos SANTOS, Tatiana de CAMPOS, and Lúcia Helena de Oliveira WADT. "Pollen and seed dispersal of Brazil nut trees in the southwestern Brazilian Amazon." Acta Amazonica 48, no. 3 (September 2018): 217–23. http://dx.doi.org/10.1590/1809-4392201800021.
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ABSTRACT Pollen and seed dispersal patterns greatly influence the spatial distribution of plant genetic diversity. Microsatellite-based parentage analysis provides accurate estimates of contemporary gene dispersal. Although most tropical trees have been shown to exhibit widespread pollen dispersal, few studies have estimated contemporary gene dispersal after seedling establishment. Bertholletia excelsa (Lecythidaceae) is pollinated by large-bodied bees, while previous seed-tracking experiments suggest their seeds are mainly dispersed across very short distances by scatter-hoarding rodents, who primarily act as seed predators. Here we used parentage analysis to provide contemporary estimates of pollen and seed dispersal in B. excelsa recruits. We examined six 25-ha plots located in two natural stands in the Acre River valley, in the southwestern Brazilian Amazon. We used 11 microsatellite markers to estimate genetic diversity and fixation index parameters in adults, seedlings and saplings. Genetic diversity was moderate and did not differ across size classes or sampling locations. We assigned pollen and seed parents for < 20% of the recruits, indicating that most events of realized gene flow occurred beyond our 25-ha plots. Only 10 parentage assignments were confirmed with 80% confidence. Pollen distance ranged from 33 to 372 m and seed dispersal from 58 to 655 m. Actual seed-dispersal distances were far greater than the estimates obtained in previous seed-tracking experiments. Thus, studies encompassing larger sampling areas are necessary to determine a more representative spatial scale of B. excelsa’s pollen and seed dispersal capacity in natural stands.
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Lapenta, Marina Janzantti, and Paula Procópio-de-Oliveira. "The Fate of Seeds Dispersed by Golden Lion Tamarins (Leontopithecus Rosalia) in an Atlantic Forest Fragment, Brazil." Tropical Conservation Science 2, no. 3 (September 2009): 266–81. http://dx.doi.org/10.1177/194008290900200301.
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Frugivores, as seed dispersers may influence the spatial patterns of adult and juvenile plants, but a large portion of the potential recruitment of plant populations is lost to seed predators. The majority of seeds dispersed by primates are killed by seed predators or moved by secondary dispersers. Little is known about post-dispersal seed-predation and seedling distribution of exploited plant species. This study iinvestigated the survival and establishment of seedlings from seeds defecated by the golden lion tamarin ( Leontopithecus rosalia), a frugivorous endemic primate of the Atlantic Forest of Brazil. Two groups of golden lion tamarins were studied in the União Biological Reserve from April 2003 to March 2004. Seeds from fruits consumed by tamarins and collected from their feces were evaluated with respect to the following: germination success, seed disappearance or secondary dispersal on the forest floor, seed predation, and seedling establishment and survival for the length of the study period. The tamarin groups consumed 88 fruit species. Of these, 38 were used to run 107 experiments which indicated that more than 50% of the seeds disappeared, about 15% died before germinating and seeds of 22 species reached the seedling stage. At the end of the study, only 15 of these species still had surviving seedlings. Studies on seed fate are important for understanding the role of the golden lion tamarind in the natural process of forest regeneration in the lowland Atlantic Forest of the state of Rio de Janeiro in Brazil.
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Villalobos-Chaves, David, Felipe P. L. Melo, and Bernal Rodríguez-Herrera. "Dispersal patterns of large-seeded plants and the foraging behaviour of a frugivorous bat." Journal of Tropical Ecology 36, no. 3 (March 31, 2020): 94–100. http://dx.doi.org/10.1017/s0266467420000036.
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AbstractMutualistic interactions are biologically important, diverse and poorly understood. Comprehending these interactions and the effectiveness of the mutualistic partners has been the central focus of ecological and evolutionary studies, as this task requires disentangling the pieces of mutualism under study. Here, we tested the hypothesis that feeding activity of Artibeus phaeotis influences density, diversity and distance effects of the seed rain of large-seeded plant species in a Neotropical dry forest of Costa Rica. We predicted that bats’ activity increases density and diversity metrics on dispersing sites and that bats behave as short-distance dispersers. Our data revealed that, by dispersing hundreds of seeds within their small foraging areas and mostly close to fruiting trees, the feeding activity of A. phaeotis increases the density and richness of seeds underneath night feeding roosts. The functional role of A. phaeotis as disperser may vary among plant species, as we also detected that some seeds are more dispersed than others. Further inquiries to elucidate mutualistic interactions between frugivorous bats and large-seeded plant species should focus on understanding demographic and fitness outcomes, as strong selective pressures may be shaping morphological and behavioural traits of both plants and animals, ultimately influencing the survival of each partner.
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Kikuchi, David W., Eloisa Lasso, James W. Dalling, and Nadav Nur. "Pollinators and pollen dispersal of Piper dilatatum (Piperaceae) on Barro Colorado Island, Panama." Journal of Tropical Ecology 23, no. 5 (August 16, 2007): 603–6. http://dx.doi.org/10.1017/s0266467407004397.
Full textAbstract:
The genus Piper is an important component of tropical forests worldwide. Many Piper species have been reported as self-compatible (Figueiredo & Sazima 2000), and many have the ability to reproduce asexually, forming clonal aggregations (Grieg 1993). Furthermore, the main dispersers of Piper (bats) transport whole infructescences to feeding roosts (Fleming & Heithaus 1981), tending to disperse closely related seeds in clumps. These characteristics of Piper biology are likely to result in populations with strongly marked spatial genetic structure, and raise the potential for inbreeding depression through self-fertilization. A few studies using allozymes to evaluate spatial genetic structure in Piper spp. support this view. These studies indicate that populations separated by more than 1 km are genetically distinct (high FST values; Wright 1943) and that for some species inbreeding could be substantial (high values of FIS and FIT; Heywood & Fleming 1986, Mariot et al. 2002). However, the contributions of limited pollen and seed dispersal to generating spatial genetic structure remain unknown. Estimates of seed dispersal probabilities by Carollia perspicillata (Phyllostomidae) bats on Barro Colorado Island (BCI), Panama, and at Santa Rosa, Costa Rica, indicate that Piper dispersers move most seeds 50–300 m from the parent plant, with occasional long-distance events of > 1 km (Fleming 1981, Thies 1998). However, no studies have assessed how far Piper flower visitors move pollen. If seed dispersal is limited, and clonal reproduction is common, then long-distance pollen transfer may play a critical role in preventing inbreeding depression in Piper populations.
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Koyama, Kohei, and Mayu Tashiro. "No Effect of Selective Maturation on Fruit Traits for a Bird-Dispersed Species, Sambucus racemosa." Plants 10, no. 2 (February 16, 2021): 376. http://dx.doi.org/10.3390/plants10020376.
Full textAbstract:
Selective abortion, also called selective maturation, is a phenomenon wherein maternal plants selectively mature ovules that have the potential to grow into higher-quality fruits, such as those that contain more seeds. We hypothesized that the effects of selective maturation on fruit traits could be influenced by the dispersal mechanism. However, to date, limited studies have been conducted on selective maturation in bird-dispersed fruits. Unlike self- or wind-dispersed species, bird-dispersed species would not selectively mature fruits that contain more seeds because they are not preferred by birds. Here, we investigated the effect of selective abortion on the fruit traits of a bird-dispersed species, elderberry (Sambucus racemosa L. subsp. kamtschatica). We performed a flower-removal experiment. Half of the inflorescences on each individual tree were removed for the treatment group, whereas the control group was not manipulated. We found that the flower-removed trees showed higher fruit sets, suggesting the existence of resource limitation. The number of seeds per fruit did not increase by the experimental treatment. Additionally, the control individuals did not produce larger fruits. The lack of effects on fruit traits supported our hypothesis that the effect of selective maturation on fruit traits may differ among species with different dispersal mechanisms.
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Yang, Yueqin, Yihao Zhang, Yinhua Deng, and Xianfeng Yi. "Endozoochory by granivorous rodents in seed dispersal of green fruits." Canadian Journal of Zoology 97, no. 1 (January 2019): 42–49. http://dx.doi.org/10.1139/cjz-2018-0079.
Full textAbstract:
Although the role of frugivores in seed dispersal has attracted scientific attention, it remains unclear whether granivorous rodents can act as frugivores to interact mutualistically with fruit-producing plants, especially those bearing green fruits inconspicuous to avian frugivores. In this study, we tracked fruit removal of the tara vine (Actinidia arguta (Siebold & Zucc.) Planch. Ex Miq.) and variegated kiwi vine (Actinidia kolomikta (Rupr. & Maxim.) Maxim.) in a temperate forest and presented fruits to the granivorous rodents Siberian chipmunk (Tamias sibiricus (Laxmann, 1769)), Korean field mouse (Apodemus peninsulae (Thomas, 1907)), and gray red-backed vole (Clethrionomys rufocanus (Sundevall, 1846) = Myodes rufocanus (Sundevall, 1846)) in the laboratory to answer this question. Seeds were collected from rodent feces to see the effects of gut passage on seed germination to determine the role of granivorous rodents in endozoochory of A. arguta and A. kolomikta. We presented clear evidence of endozoochory by granivorous rodents in seed dispersal of the two Actinidia species. Rodents appeared to play an alternative role in dispersing plants bearing green fruits. Moreover, we observed increased germination rates after gut ingestion by the granivorous rodents. Our study evidenced endozoochory of granivorous rodents and provided new insight into the mutualist interactions between rodents and plant species bearing fleshy fruits containing tiny seeds. We suggest future studies pay more attention to endozoochory of rodents and establish their mutualistic relationship with fruit-bearing plants in temperate forests.
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Orrock, John L. "The effect of gut passage by two species of avian frugivore on seeds of pokeweed, Phytolacca americana." Canadian Journal of Botany 83, no. 4 (April 1, 2005): 427–31. http://dx.doi.org/10.1139/b05-016.
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Although avian frugivores are known to be important dispersers of seeds of pokeweed, Phytolacca americana L., there are no studies that rigorously examine the effect of gut passage through avian frugivores on P. americana seeds. I examined how passage through avian frugivores affected the proportion of P. americana seeds germinating, the rate of germination (average number of days required for all seeds to germinate), and the total number of viable seeds. Field-collected fruits were either cleaned of pulp (control seeds), fed to northern Mockingbirds (Mimus polyglottos), or fed to Brown Thrashers (Toxostoma rufum). The proportion of seeds germinating after passage through avian frugivores was greater than control seeds (0.88 vs. 0.67, respectively), but did not differ between Mockingbirds or Brown Thrashers. However, seeds consumed by Mockingbirds germinated significantly faster on average (4.2 d) compared with seeds consumed by Brown Thrashers (4.6 d). Consumption by either species led to faster germination than control seeds (5.5 d). The total number of viable seeds did not differ among seeds consumed by avian frugivores or control seeds. These results suggest that avian frugivores do not change the viability of P. americana seeds. Rather, avian frugivores shifted the timing of germination, such that more seeds germinate more quickly after passage through frugivores. The adaptive implications of accelerated germination following passage through frugivores are briefly discussed.Key words: dispersal, frugivore, germination, viability.
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Zhang, Hongmao, and Wei Wang. "Using endocarp-remains of seeds of wild apricot Prunus armeniaca to identify rodent seed predators." Current Zoology 55, no. 6 (December 1, 2009): 396–400. http://dx.doi.org/10.1093/czoolo/55.6.396.
Full textAbstract:
Abstract Some rodent-dispersed seeds have a hard seed-coat (e.g.woody endocarp). Specific scrapes or dental marks on the hard seed-coat left by rodents when they eat these seeds can be used to identify seed predators. In this study we measured the morphological traits of endocarp-remains of seeds of wild apricot Prunus armeniaca used by Chinese white-bellied rats Niviventor confucianus and Korean field mice Apodemus peninsulae. We established their Fisher’s linear discriminant functions to separate endocarp-remains between the two predators. A total of 90.0% of the endocarp-remains left by Korean field mice and 88.0% of those left by Chinese white-bellied rats were correctly classified. The overall percentage of correct classification was 89.0%. One hundred and sixty endocarp-remains of unknown what species predated them were classified using the functions. The method may allow more reliable quantitative studies of the effects of Chinese white-bellied rats and Korean field mice on seed consumption and dispersal of wild apricot and this study might be used for reference in other studies of seed predators identification on hard seeds.
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Zasada, John C. "Embryo growth in Alaskan white spruce seeds." Canadian Journal of Forest Research 18, no. 1 (January 1, 1988): 64–67. http://dx.doi.org/10.1139/x88-010.
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Embryo development in white spruce seeds was studied in five stands in interior Alaska. Cones and seeds were collected at 10- to 14-day intervals starting in mid-July and continuing until just before seed dispersal began. Significant differences were found in embryo development between stands, between trees within stands, and between cones within trees. The four stands at lower elevations produced seeds that had embryos filling 95% or more of the embryo cavity; this percentage was significantly higher than the highest elevation stand where embryos filled about 75% of the embryo cavity at the end of the growing season. Relative cotyledon length was generally greater than 25% in the lower elevation stands and slightly less than 20% in the high elevation stand. Although seed collection can be started when embryos fill 75% of the embryo cavity, the results of this and other studies suggest that collecting seeds when embryos are more mature will result in better quality seeds. Air and soil temperatures and soil moisture levels associated with embryo development are presented.